A semiconductor chip comprising an integrated circuit can be provided with optical components to enable a performance of both optical functions like optical data transfer, switching, multiplexing and modulation and electronical functions like data processing. An integration of the optical components is desired to obtain compact dimensions. An integrated waveguide may be used for a transfer of optical signals. Mirrors are suitable to couple radiation from an external source into the waveguide and to reflect radiation propagating in the waveguide towards external optical devices.
U.S. Pat. No. 5,373,570 A discloses a process for producing a device structure with integrated optical waveguide and mirror. A substrate is etched according to a crystalline plane to form an inclined planar surface. Various layers are epitaxially grown on the substrate to form an optical waveguide. The substrate is removed from the rear side to uncover the inclined plane, thus forming a mirror reflecting light from the optical waveguide in a given direction. A deposition of a metallization on the back of the mirror is proposed to improve its reflective qualities.
US 2013/0121354 A1 discloses an optical interconnection system for a plurality of semiconductor devices including surface emitting laser arrays connected via silicon optical waveguides comprising a plurality of optical couplers and splitters. The waveguides comprise a core portion confined by cladding portions of lower refractive index. In the core portions, a plurality of reflecting portions are formed by groove processing at positions above each of the surface emitting laser devices to reflect the laser light into the core portion.
EP 1 818 701 A1 discloses an opto-electronic interfacing device for mounting on a printed circuit board. Optical waveguides are formed in a substrate, and an optical connector is attached to the substrate and optically aligned to one or more of the waveguides, which may form an optical splitter/combiner. An integrated mirror is formed on an inclined end face of the substrate provided with a mirror finish to reflect optical signals entering or emerging from the waveguides through substantially 90° with respect to the plane of the waveguide layer.
The publication of S. V. Nguyen, “High-density plasma chemical vapor deposition of silicon-based dielectric films for integrated circuits”, IBM Journal of Research & Development vol. 43(1/2) (1999), pp. 1 to 19, describes various technical details of high-density plasma chemical vapor deposition, in particular for the formation of interlevel insulation, gap filling, and planarization.